Kurdish and Arab forces backed by the U.S. have entered Islamic State's de facto capital of Raqqa, setting the stage for what could be a months-long campaign to reclaim the militants' largest stronghold in Syria.
The airstrikes are reported to have targeted the Mashlab district east of the old city, where the Kurdish forces are advancing. The strikes are believed to have killed dozens of Syrian soldiers and Iranian-backed militia forces, in addition to destroying tanks and heavy weapons.
Syrian government warplanes struck Islamic State positions west of Raqqa city on the southern bank of the Euphrates river on Thursday, state media said.
The monitor said there were at least 25 strikes, with most of the civilians killed as the planes hit an internet cafe in the western suburb of Jazra.
SDF spokesman Talal Sello said fighters were advancing against ISIS on several fronts. "They then advanced north to the adjacent district of Al-Romaniya and are fighting IS there", he told AFP.
"IS has snipers monitoring Al-Meshleb neighbourhood and has laid mines extensively throughout it", the monitor said.
Al-Meshleb was the first neighborhood in Raqqa city entered by SDF fighters.
Speaking to Kurdistan24, Jihan Sheikh Ahmad, the spokesperson of operation room in Raqqa battle, said the SDf liberated al-Mishlab district at the city's southeastern outskirts. On Thursday, the US shot down an armed drone it said had attacked its units embedded with local opposition forces in the region.
They have also reportedly dug defensive trenches and tunnels to try to slow the SDF advance.
"Hundreds" of USA military personnel are taking part in the Raqqa offensive, according to the Pentagon, which said Thursday it believed up to 2,500 extremists were still holed up in Raqqa. It has also emerged as a hub for planning attacks overseas.
An estimated 300,000 civilians were believed to have been living under ISIS rule in Raqqa, including 80,000 displaced from other parts of Syria.
But thousands have fled in recent months, and the United Nations humanitarian office said on Tuesday that it estimated about 160,000 people remained in the city. Photo Credit: Mohamad Abazeed/AFP via Getty Images "An estimated 40,000 children remain trapped in extremely risky conditions in Raqqa".
Its regional spokesman David Swanson said as many as 100,000 people "may stay trapped" inside during the assault. He urged all parties to give safe passage to those who want to leave.
"Parents have to make an impossible decision", said MSF emergency coordinator Puk Leenders.
The SDF has scored a series of victories since launching its operation to take Raqa in November, including capturing the strategic town of Tabqa and its adjacent dam in May.